In general, a fuel pump of a vehicle is mounted on the inside of a fuel tank of the vehicle and serves to suction fuel and pressure-feed the suctioned fuel to a fuel injection device mounted in an engine.
In addition, the fuel pump for the vehicle is classified into a mechanical fuel pump and an electrical fuel pump and a turbine type fuel pump 10 which is a type of electrical fuel pump is primarily used in an engine using gasoline as fuel.
In the turbine type fuel pump 10, a driving motor 20 is provided in a motor housing 60 of the fuel pump 10, an upper casing 30 and a lower casing 40 are provided on the bottom of the motor housing 60 to be closely attached to each other, and an impeller 50 is interposed therebetween, as shown in FIG. 1.
In addition, the impeller 50 is joined to a rotational shaft 21 of a driving motor 20, such that the impeller 50 is configured to rotate with the driving motor 20.
That is, as the impeller 50 rotates, a pressure difference is generated, and as a result, fuel is suctioned into the impeller 50 and while the pressure of fuel is increased due to a rotation flow generated by continuous rotation of the impeller 50, fuel is ejected.
Therefore, fuel is introduced into a fuel suction opening 41 of the lower casing 40 to flow to a check valve 70 formed in an upper part of the motor housing 60 along an inner part of the motor housing 60 through a fuel ejection opening 31 of the upper casing 30 with the pressure thereof increased through the rotating impeller 50 and supplied to the fuel injection device mounted on the engine of the vehicle.
In this case, the impeller 50 is formed in a disk shape, a plurality of blades 51 are formed on an circumferential surface thereof in an outer direction of the circumferential surface, blade chambers 52 are formed among respective blades 51 to penetrate both surfaces of the impeller 50 as shown in FIG. 2, such that fuel is introduced into the fuel suction opening 41 of the lower casing 40 to generate the rotation flow in a space between the blade chamber 52 and a lower path groove 42 formed in the lower casing 40 and an upper path groove 32 formed in the upper casing 30 as shown in FIG. 3, and a circulation process in which fuel is again introduced into the neighboring blade chamber 52 to generate the rotation flow is repeated. Therefore, kinetic energy generated by the rotation of the impeller 50 is converted into pressure energy of fuel, and as a result, fuel is delivered to the fuel ejection opening 31 of the upper casing 30.
In addition, in the impeller 50 in the related art, a circumference center guider 53 is formed at the center of the circumferential surface along the circumferential surface of the impeller 50 so as to efficiently generate the rotation flow formed in the space between the blade chamber 52 and the lower path groove 42 and the rotation flow generated in the space between the impeller chamber 52 and the upper path groove 32.
However, with a current technological trend in which components in the vehicle are gradually subjected to a light weight, a compact size, and high performance in order to satisfy user's various preferences globally, a study about high performance of even the fuel pump has been required.
In addition, the amount of used pressure of the fuel pump is determined according to a specification of the vehicle and a high pressure is required as a recent trend. Therefore, the fuel pump mounted with the impeller in the related art is limitative in increasing an ejection amount of fuel under high pressure.